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Discussion Starter #21 (Edited)
Well once I get this figured out, I will be ready to go with some upgrades. Just placed an order with Riffraff.


FRx Fuel Rail Crossover™
Fuel Pressure Relief Rebuild Kit
Motorcraft Fuel Tank Pickup Foot and Screen
Parker 60VLV-5 Viton Sleeve 5/16 inch
Riffraff SS HPX 99-03
HPOP Pressure 0-4000 PSI

Oh and I've got a Pre-pump setup coming from Driven Diesel.
I am kinda tired of messing with this so I want to go ahead and do it all at once.
 

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Are you doing the in-tank mods to get rid of the screens and mixing valve?

Since you are getting the pre-pump filter, you might want to make this the last trip into the tank and eliminate that mixing valve / duckbill set-up.
 

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Discussion Starter #23

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Discussion Starter #24
I finally got around to installing the pre pump kit from Driven/strictly Diesel.

I was a pretty decent kit for the price, the filter head was made in China, not USA like they claimed. The install was a bit frustrating, but I attribute most of this to the fact that I have a Regular cab 4x4 and there was not much room for the filter between the tank and the T-case.

Anyway, after installing this kit, the FRX, a fully rebuilt FPR, and a new pickup umbrella, I still have very poor fuel pressure. I think it is actually worse after installing the pre pump kit.

Just to throw in some more info, I do have a few DTCs

P0238 (overboost..no concern)

p0475 (gutted EBPV...no concern)

p1211 ( IPR uncontrollable... Im hoping this is caused by the low fuel pressure)

P1209 (same as 1211, right?)

P1668 (IDM comminucation fault. Not sure about this one. I have checked the fuse, but I dont think its related to my current issue. I would like to get ti figured out though)

Im thinking the 1 month old pump may be no good. I have another one to swap in, and will probably try that tomorrow. Then again, I may hold out for a raptor 150gph and just not have to worry about it again.
Any thoughts?
 

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Discussion Starter #25
Just swapped out the fuel pump again for another brand new one. No change.
wow!:icon_mad: this is frustrating.
 

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Discussion Starter #26
My buddy is telling me to put UV dye in my fuel tank and pull the valve covers to see if I have any leaks around the injector O-rings.
I just put all new injectors in last May, so I cant imagine they could be leaking already, but if it solves this problem, I will gladly fix it.
I still have a whole set of injector seals that came with my cup kit.
I certainly cant think of anything else that would be causing this.
 

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You could tell this easier by seeing if your oil level is rising. If the pressures are down like you say, it should fill the crankcase with fuel in just a few minutes. Likewise, if you had a cracked injector cup, your degas bottle would be full by now.
 

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My buddy is telling me to put UV dye in my fuel tank and pull the valve covers to see if I have any leaks around the injector O-rings.
That won't work.

There's no way that 50 psi (nominal) UV dyed fuel is going to get by the middle o-ring that separates the fuel gallery from the 500+ psi oil gallery, and then past the top o-ring to show up under the valve covers.

I doubt your issue is injector o-rings.
 

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Discussion Starter #29
Oil level is normal, and does not even have a hint of diesel smell to it.

I agree with you RT, if that were my problem, I should have a full crankcase by now. I have been experiencing this problem ever since shortly after I installed my fuel pressure gauge. I really need to figure it out.
 

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Haven't read through all of the posts, but have you checked the FPR?

Sent from AutoGuide.com App
 

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Discussion Starter #31
Haven't read through all of the posts, but have you checked the FPR?

Sent from AutoGuide.com App
Yes, I have completely rebuilt the FPR and used the black spring when I installed the FRX.

Today I removed the factory fuel filter hoping to find something going on inside the bowl. I hooked a line to the drain and had my wife turn the key so I could watch the bowl fill. The stream of fuel coming into the bowl looked ok, and when I put my finger over the hole, I could feel pressure build and hear the tone of the pump change. A few minutes later I put it back together and headed off to work. For the first 3 minutes of that trip I had pretty good fuel pressure. I was even able to hit 30 psi Boost for the first time in a month. I did a few joyous romps in the 120 tune on the way to the highway. I forgot how much fun this truck was when it worked right. Then after about 2-3 minutes of driving the pressure started to drop again and I was back to feeling like I had a Briggs & Stratton under the hood.

The good news in all of this is that for a long time, I have thought my trans was messing up. Now I think it has all been related to fuel pressure. During those 3 minutes, My trans shifted perfectly. That's another story in itself.
 

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When you did the pre-pump kit, did you completely replace the fuel supply line between the tank and the pump? It sure sounds to me like there's something on the inlet side of the pump that's restricting flow. When I did my pre-pump mod, I completely bypassed the steel line with the sections of hose at the tan and pump, using just a hose running all the way from the pickup to the pump with the inline filter in-between. Maybe the hose section near the tank got pinched or kinked when the tank was installed at one time and now has a spot that collapses under suction after a bit.
 

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Discussion Starter #33
Yes, I replaced the supply line between the tank and pump with the hose that came with the kit from driven diesel.

It does go thru some tight bends, and I was very careful not to kink the hose during the tank install. The only thing factory before the pump is the section of steel line inside the tank.

Im really starting to suspect the viscosity of my wmo mix. I think I will try straight d2 on the next tank.
 

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Discussion Starter #34
Ok, new info:

Over the last couple of days, I have noticed a trend.
When the truck has been sitting for at least a couple hours, the fuel pressure is better. It can be cold or even still a bit warm, but when I first start it, I can get great performance and much better pressures ([email protected] [email protected]). After about 10 minutes it has gotten so bad, it will idle at 45 psi, and drop to 0 at wot. Last night I disconnected the supply line and ran the pump until it filled a 5 gal bucket. Everything looked ok. What could be going on here?
 

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Pressure is determined by several factors - flow, resistance, viscosity, tubing diameter all affect the final value. Poiseuille's Law is the formula it would be based on. You need to try and isolate these variables and eliminate them one by one. Viscosity should be fixed. Resistance is determined by the FPR, which you've rebuilt. We're assuming you got everything back together properly, so if that's a possible bad assumption, you could pull it apart again and follow the instructions on Bob's website line by line. Other restriction points that would negatively affect fuel pressure would be screens / filters before the FPR. Anything after that would increase pressure. We also have to assume your fuel injectors are using the proper amount of fuel - if one of them was dumping at such a rate that it affected your fuel pressure, you should be hearing the knock. Likewise, a leak affecting the pressure that much would have to be identified by the massive quantities of fuel that would be showing up. That pretty much leaves flow provided by the fuel pump. You've swapped pumps a few times, so unless you're the unluckiest customer at the auto parts store, hopefully you've got that covered. So - all the basics are covered. What's left? A restriction somewhere in the supply side or possibly in the pump to fuel bowl line. I'm betting on the supply side based on the way your pressures drop so much with variations in throttle. Its acting like a bad pump / plugged filter dropping so much at WOT. I've run pure WMO with no variations in pressure - and I monitor fuel pressure full time.

If I were you, I'd drop the tank again - triple check your work. Make sure the rubber hose on top of the tank isn't kinked. You wouldn't be the first person to do the Hutch mod to get that line kinked. Solve one problem and create another. That's why I like to do tank work by pulling the bed - don't have to do all those connections by Braille. You could rig up a milk jug with diesel and a line to the pump and take it for a test drive. If that makes a difference on your WOT run, you know you've got a tank issue. Do it before and after your new pre-pump filter setup to rule that out too.
 

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Discussion Starter #36
We also have to assume your fuel injectors are using the proper amount of fuel - if one of them was dumping at such a rate that it affected your fuel pressure, you should be hearing the knock.

Make sure the rubber hose on top of the tank isn't kinked. You wouldn't be the first person to do the Hutch mod to get that line kinked. Solve one problem and create another.
Wow RT thanks for the input!:thumbsup:

I have been waiting to hear from somebody regarding the WMO visco.
My truck does have a "knock" (rough idle?) sometimes, But I always attributed it to the low fuel pressure and crappy blend of WMO.

As far as the kinked line, I will feel around @ my 10:30 break.
(I work 2nd shift)

If one or more of my injectors were dumping fuel, Is there another way I could tell this besides the sound of the engine? I guess I don't feel too confident in my ear.
 

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You'd know it- it sounds like a half dozen thrown rods all at once.


Sent from AutoGuide.com App
 

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Discussion Starter #38
Guess I can rule that out.:eek3:
 

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Here's just one injector tip broken -
That wouldn't even be enough to affect fuel pressure...
 

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Discussion Starter #40
nope, mine's definitively not anywhere near that bad. Id be scared to stand next to that.:worried:
 
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